a. Field of Invention
The invention relates to radio receivers and, more particularly, to an autonomous radio receiver capable of receiving a signal without a priori knowledge about the defining characteristics of the signal, recognizing these characteristics directly from the received signal, and appropriately decoding the signal based on the signal type.
b. Background of the Invention
Conventional radio receivers typically have complete prior knowledge of the defining characteristics of signals they are designed to receive. Because conventional radio receivers know what type of signal they are going to receive they are typically hardwired or manually configured to do so. Conversely, conventional radio receivers are incapable of receiving signal types different from that which they were intended for. In some cases where they do have such capability, conventional radio receivers require specific pre-configuration according to a pre-determined schedule. Thus, conventional radio receivers are capable of only receiving pre-determined/pre-programmed types of signals. For example, cellular telephones are designed according to several different standards, and single-mode telephones are typically preconfigured to receive only one type of cellular telephony signal. Indeed, a single-mode telephone configured to use Code Division Multiple Access (a popular system in the United States) is unable to receive a signal using Global Systems Mobile (GSM) signals, which is the European standard. While there are dual-mode telephones to solve the CDMA/GSM dichotomy, there remains the issue and potential future issue of varying frequency bands, data rates, modulation types, modulation indices, pulse shapes, and so on, which may affect the usability of cellular telephones. Therefore, there is a need for a system capable of receiving multiple signal types without a priori knowledge about the defining characteristics of the signals, and accurately recognizing defining features of the incoming signals and respond intelligently without explicit pre-configuration or reprogramming to define the functions of the receiver. In other words, there is a need for a system capable of recognizing multiple signal types and autonomously reconfiguring itself to decode the particular type of signal that is received.